ALERT: Flash Flood Watch in effect for Oahu through Friday

HONOLULU—The National Weather Service in Honolulu has placed the island of Oahu under a Flash Flood Watch effective from 6:00 p.m. on Wednesday, November 17 through the afternoon of Friday, November 19. A Flash Flood Watch means that conditions may develop that lead to flash flooding.

Several factors contribute to flash flooding—particularly rainfall intensity and duration. Intensity is the rate of rainfall, and duration is how long the rain lasts. Topography, soil conditions, and ground cover also play an important role.

Flash floods occur within a few minutes or hours of excessive rainfall. Flash floods can roll boulders, tear out trees, destroy buildings and bridges, and scour out new channels. Rapidly rising water can reach heights of 30 feet or more. Furthermore, flash flood-producing rains can also trigger catastrophic mud slides. There is never a guarantee for a warning that sudden floods are coming. Most flood deaths are due to flash floods, according to the National Oceanic and Atmospheric Administration National Weather Service (NOAA).

All residents should monitor TV and radio broadcasts during the watch period and be prepared to take immediate action should a Flash Flood Warning be issued.

The Department of Emergency Management urges residents and businesses to consider the following flood safety precautions:

· Know the meanings and effects of a Flood Advisory, Flash Flood Watch, Flash Flood Warning. If some flooding has begun to occur, a Flood Advisory will be declared. A Flash Flood Watch means that flash flooding is possible within the designated watch area, so be alert. A Flash Flood Warning means flash flooding or flooding has been reported or is imminent—take necessary precautions at once.

· Learn the safest route from your home or place of business to high ground should you have to evacuate in a hurry.

· If your area floods frequently, keep emergency materials on hand such as sandbags, plywood, plastic sheeting, and lumber, which can be used to protect properties.

· Stay away from areas along streams or near drainage canals/ditches. These areas can become deadly during periods of heavy rainfall.

· If your car stalls in a flooded area, abandon it as soon as possible. Floodwaters can rise rapidly and sweep a car (and its occupants) away. Many deaths have resulted from attempts to move stalled vehicles. Do not attempt to drive through flooded areas in your vehicle as parts of the road may already be washed out or the water may be much deeper than it appears. Turn around, don’t drown!

· Consider canceling or postponing outdoor activities, especially hiking in mountains and valleys. A small stream can become a raging torrent within minutes if previous rainfall has been substantial. Don’t cross until the flash flood subsides.

· Heavy rains cause runoff, which attracts more sharks. Avoid swimming immediately after a heavy storm, especially in murky waters.

· If you experience a flood related emergency call 9-1-1 immediately.

Visit the National Weather Service website at http://www.prh.noaa.gov/hnl/ for more information and current weather advisory status or call the National Weather Service at (808) 973-5286 for recorded weather information. Also monitor television and radio for the latest updates.